Quran 66:4

إِن تَتُوبَآ إِلَى ٱللهِ فَقَدۡ صَغَتۡ قُلُوبُكُمَا‌ۖ وَإِن تَظَـٰهَرَا عَلَيۡهِ فَإِنَّ ٱللَّهَ هُوَ مَوۡلَٮٰهُ وَجِبۡرِيلُ وَصَـٰلِحُ ٱلۡمُؤۡمِنِينَ‌ۖ وَٱلۡمَلَـٰٓٮِٕڪَةُ بَعۡدَ ذَٲلِكَ ظَهِيرٌ ٤

If the two of you repent to ALLAH, then your hearts have listened. But if you band together against him, then ALLAH is his ally, and so is Gabriel and the righteous believers. Also, the angels are his helpers.